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A chloroplast pathway for the de novo biosynthesis of triacylglycerol in Chlamydomonas reinhardtii
Author(s) -
Fan Jilian,
Andre Carl,
Xu Changcheng
Publication year - 2011
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2011.05.018
Subject(s) - chlamydomonas reinhardtii , chloroplast , biosynthesis , diacylglycerol kinase , biochemistry , chlamydomonas , endoplasmic reticulum , lipid metabolism , biology , cytosol , metabolic pathway , yeast , microbiology and biotechnology , metabolism , enzyme , gene , mutant , protein kinase c
Neutral lipid metabolism has been extensively studied in yeast, plants and mammals. In contrast, little information is available regarding the biochemical pathway, enzymes and regulatory factors involved in the biosynthesis of triacylglycerol (TAG) in microalgae. In the conventional TAG biosynthetic pathway widely accepted for yeast, plants and mammals, TAG is assembled in the endoplasmic reticulum (ER) from its immediate precursor diacylglycerol (DAG) made by ER‐specific acyltransferases, and is deposited exclusively in lipid droplets in the cytosol. Here, we demonstrated that the unicellular microalga Chlamydomonas reinhardtii employs a distinct pathway that uses DAG derived almost exclusively from the chloroplast to produce TAG. This unique TAG biosynthesis pathway is largely dependent on de novo fatty acid synthesis, and the TAG formed in this pathway is stored in lipid droplets in both the chloroplast and the cytosol. These findings have wide implications for understanding TAG biosynthesis and storage and other areas of lipid metabolism in microalgae and other organisms.